Research proposed in the clinical Cerebrovascular Research Center for the next year is a continuation and logical extension of ongoing projects previously demonstrated to be productive. The project entitled Pathogenesis of Atherosclerosis utilizes the scanning electron microscope in conjunction with other techniques to investigate the hypothesis that detectable endothelial cell damage occurs prior to and is a necessary prerequisite for the development of atherosclerosis. The Pathophysiology of Subarachnoid Hemorrhage and Cerebral Vasospasm project proposes to study experimental subarachnoid hemorrhage in dogs by monitoring cardiovascular, respiratory and intracranial pressure parameters and studying the pathogenesis and sequelae of vasospasm in inducing thrombosis, embolism and brain infarction. The Puberty and Atherosclerosis project seeks to determine the effects of a high cholesterol diet during early life on the development of hypercholesterolemia and fatty streaking in later life in pigs. The Vascular Innervation project studies the automonic innervation of the macro and microcirculation by flourescence histochemistry and electron microscopy. The project entitled Cerebral Infarction Pathogenesis and Evolution will investigate experimental cerebral infarction in mouse brain by measurement of ions and amino acid concentrations correlated with electron microscopy observations to determine the effects of fixation, the degree of perfusability of infarcted brain and the nature and topographic distribution of structural abnormalities over time.